Duration of hepatitis C virus (HCV) infection is a key feature
in determining responsiveness to interferon (IFN). Studies
assessing its value as a predictive factor in chronic HCV infection
show that a long duration of infection reduces the likelihood of a
sustained response to IFN (defined as ALT normalization and
clearance of serum HCV-RNA). The effect of HCV infection duration
is independent of the presence of cirrhosis and level of HCV
viremia. Meta-analysis of IFN trials in acute HCV infection shows
an obvious effect of the drug on long-term ALT normalization and
HCV-RNA clearance. Treatment of HCV infection during the acute or
early chronic phase could therefore maximize therapeutic
effectiveness.